1. Technical Field
The invention is related to video cassette recorders and video cassettes having a feature, now standard in the industry, of an anti-erase switch comprising (in the case of 8 mm video cassettes) a mechanical slide near a particular corner of the cassette housing. VHS cassettes have a break-away tab, instead of a slide switch. Whenever, the anti-erase switch is in the "ON" position, the video cassette recorder prevents itself from recording on the video cassette, thus insuring preservation of any material previously recorded on the cassette.
2. Description of the Problem
The problem is how to record on a video cassette having previously recorded material thereon, which must not be erased, without risking erasure of the previously recorded material. For anyone familiar with home video cassette recording systems, erase protection for recorded programs such as irreplaceable scenes from family history, etc., is an essential feature. However, in order to protect a video cassette storing such valuable material, the standard anti-erase switch must be moved to the "ON" position, which makes that cassette useless for any further recording, even though it is likely that when such protection is first required, a large portion of the cassette remains unused. The problem is that the user will later attempt to record in unused portions of the cassette and therefore must deactivate the anti-erase switch. This creates two problems. First, the user is likely to forget to reset the anti-erase switch when finished. Secondly, it is highly inconvenient to search through a two-hour video cassette (for example) for that portion of video tape which remains unused.